A Heading

Markdown is intended to be as easy-to-read and easy-to-write as is feasible.

Readability, however, is emphasized above all else. A
Markdown-formatted document should be publishable as-is, as plain
text, without looking like it’s been marked up with tags or
formatting instructions. While Markdown’s syntax has been influenced
by several existing text-to-HTML filters, the single biggest source
of inspiration for Markdown’s syntax is the format of plain text
email.

A Smaller Heading

Arbitrary HTML tags can also be used, such as span
tags to set colours. Not that I’d do that of course.